This invention relates to a system for recirculating sealing liquid that has leaked from a liquid seal portion of a Stirling engine back into the liquid seal portion.
Stirling engines have received increasing attention in recent years owing to their high torque characteristics, clean exhaust gases, low noise, low fuel expense, low maintenance, and high durability when compared with a conventional gasoline engine. Furthermore, the thermal efficiency of a Stirling engine is equal or superior to that of the internal combustion engine because in a Stirling engine hydrogen or helium is used as the working fluid instead of air, and hence the temperature efficiency of the thermal heat exchangers is greatly improved.
However, since hydrogen or helium as the working fluid has a relatively small molecular structure, it is difficult to properly seal a Stirling engine. Stirling engines have accordingly exhibited high leakage rates in the sealing area between the cylinder wall and the piston rod. Conventional "roll sox" seals have been reasonably effective but their durability is low due to the choice of materials used therein.
Recently, multiple seal rings have been used to form a compound seal with a block seal portion and a liquid seal portion positioned therebelow in order to enhance durability.
However, the problem of leakage of the sealing liquid used in the liquid seal portion has remained, and research to solve this problem has not defined a suitable mechanism therefor. Hence, the problem of leakage remains and an effective engine must take such leakage into account.